Vibratory screening apparatus



April 4, 1961 K. MULLER VIBRATORY SCREENING APPARATUS 2 Sheets-Sheet 1 Filed Dec. 25, 1957 Inventor K u MULLER ATTORNEYS Apr1l4, 1961 LLER 2,978,104

VIBRATORY SCREENING APPARATUS Filed Dec. 23, 1957 2 Sheets-Sheet 2 UPPER HALF- OSCILLATION ACCUMULATOR ING ACCUMULA LOWER HALF-OSCILLATION COMBINATI -CURVE ACCUMULATOR $PR|NG+ ANTI- GRAVITY SPRING FIG.4.

ATTORNEY 5 I 12,978,104 'VIBRATORY SCREENING APPARATUS KurtMiiller, Nordstr. '32, Recklinghausen, Germany Filed Dec. 23, 1957 ,Ser. No. 704,831

'2 Claims. (Cl .-209-365) r Schieferstein-screening machines, that is screening machines which operate'on the system of two masses and which are built up from separate sections supported on ments are mounted on transverse beams which turn are oscillatable in pivot hearings on both sides. The pivot bearings are mounted for rotation in the base frame members. -For maintaining in central position the inclined suspended"scren'fianie'stipport elements, which'are'pulled downwards by the force of gravity, so-called anti-gravity springs are used. The arrangement of these anti-gravity springs in the known Schieferstein screening machines has not always been solved in a satisfactory manner; in par- 2,978,104 Patented A A, 1961' I 12 are provided which are mounted also in the pivot bearcushioning springs, are known, in which the-screen eleticular the central or middle position of the inclined e suspended screen frame support elements is not always ensured or adjustable for any angle of throw and the mass equilibrium of the whole apparatus is destroyed when the length thereof is changed by connecting up or disconnecting the individual sections.

The invention has for its object to' ensure the central position of the screen frame elements suspended at an incline at all angles of throw and to enable changes to be effected in the length of the whole apparatus by connecting up or disconnecting individual sections, without disturbing the mass equilibrium.

' The invention relates to Schieferstein screening ma- .chines composed of separate sections supported on cushioning springs, in which the screen frame; elements are mounted on transversebeams 'andthe latter are oscillatably arranged at both ends in pivot bearings which have their running fit in-the base frame members, and this invention consists in adding anti-gravity springs to take up the mass weight of the transverse beams and the screen frames, and these are arranged at the ends of the transverse beams, A' preferred form of construction is char acterized by' thefact that the springs are adjustable between the spacerguides of thepivot bearings. An embodiment of the invention is illustrated by way' ofjexample in' the accompanying drawing, in which:

Fig. 1 shows the screening machine in side elevation;

Fig. 2 shows a pivotbearing on a larger scale;

Fig. 3 is a section taken on'line A,.A'.of Fig. 2; and

Fig. 4 shows a diagrammatic sketch of the operation of the invention.-

The screen frame elements 1 of ascreening machine a composed ofseven separate sections arranged in series and resiliently interconnected, are-mounted on transverse beams), which are .o'scillatable in bearings 4,;bymeans of link springs 3; ,The pivot bearings 4'aremounted for rotation in base frame membersS and'can be'adjusted' for a great variety of angles of, throw. Anti-gravity j springs 7 providedwith' clamping' heads 8 are rotatably secured on the ends of theftransverse 'beamsjcornposed i i for example of carrier tubes,;,by meansof'welded-on journals 6 and are seatediin'aspring plate 9 which'is slidable. onspacer guides 10 of the pivot bea1'iug s4 and firmlyseated with the faidof nuts 11'. :;;Be tween the counter ings.

The whole apparatus is mounted on cushioningsprings '13.

The novel construction and arrangement according to 'the invention render it possibleto impart to the anti- 'gravity springs 7 the pretension necessary for anyangle of throw to exert a pressure corresponding to the gravity components of a transverse beam with its screening jelement, until the individual screening elements are brought into central balanced position.

Fig. 4 shows the action of a typical Schiefer'st'ein screening system using the particular anti-gravity springs of this invention. The path of operation of the screen is seen :in Fig. 4 by following the solid line from the upper lefthand corner to the lower right-hand corner. From one isga'short transverse interval of'play until such a time the play on the lower side. At this point-the manner of 1 operation is alongthe dotted line, whichis actually the anti-gravitysp'ring line. This is an additionalspring which is added to the system in order to provide for additional resistance on the lower side and to overcome the effect of gravity upon the system. Instead of the normal upper line, which is shown in the lower right-hand corner, the accumulator spring line, the combination curve of the accumulator spring and the anti-gravity spring should be noted because the force of the combination for any particular distance is always greater than the same distance for the upper accumulator spring. In this view, the upper half oscillation of the screen is shown in the upper lefthand corner, while the lower half oscillation is shown in the lower right-hand corner. v

To more fully understand the operation of thisinvention, thetwo-mass Schieferstein screening machine should be described as consisting of seven units supported on insulating springs 13. Each unit is a two-mass system in itself, which iscomposed of a vibrating mass having spring frame elements 1 and transverse beams 2 and a counter oscillating mass having pivot bearings 4 in the base frame members 5. The screen frames are con-' nected to the transverse beams 2 which at the ends are suspended in pivot bearings 4. These pivot bearings are adjustable and can be moved around the unit. At each pivot bearing the accumulator springs 12, of rubber generally, on both sides of the transverse beam, are mounted so that they may be oscillated from a central or middle position upwardly and downwardly, perpendicular to the link or leaf springs 3. In the drawings the.

amount of play which takes place between the'transverse beam and the accumulator spring is shown. Furthermore, acording to this invention, the anti-gravity springs are mounted to eachrpivot bearing 4 (see Figs. 2 and 3) to the journals in a direction perpendicular to the link or lleafspringsy This arrangement of anti-gravity springs practically affects the lower half of the oscillation of this screening system, and does so by providing a combinationof the accumulator spring and the anti-gravity spring to carry a doubleelfect. The anti-gravity springstake' over i oscillating masses 1td2sand4to5,accumulator springs Fig. 4,. there.' .is' a icert aingmpunt f pmy injihg System I 1 from the middle or central position of the vibrating system between the oscillating masses and the accumulator spring. This motion or play is a characteristic feature of the unharmonic vibration process and is intended. The size of such motion or play isadjustable; Theantigravity springs set the central postion of the oscillating mass, and a more regular striking of the oscillating masses to the accumulator springs is possible. This more regular action results in prolonged durability of the accumulator springs and, as well, a new combination of the antigravity and accumulator springs improves the mass compensation of the total system.

The advantage of this system is that each one of the separate screen sections may be centered at a different angle. The anti-gravity springs can be adjusted forthe particular component of gravity involved. These may be adjusted to fit the screens in question so that the natural tendency of the springs to sag with the weight thereon will be offset. This is true not only of the static condition but of the dynamic condition also. Balance is thus achieved with the particular conditions on the screen.

Another advantage of the novel arrangement of the anti-gravity springs is that the mass equilibration of the whole machine is not disturbed even in the event of subsequent change in the total length thereof by connecting up or disconnecting individual sections.

1 claim:

1. A vibratory screening apparatus of the counter oscillating type supported on cushioning springs and composed of a plurality of individual sections, each of which is composed of a pair of longitudinal base frame members, a transverse beam with a screening frame element secured on said beam, pivot bearings mounted for rotation in the longitudinal base frame members and supporting said transverse beam at both ends with said pivot bearings, each having mounted therein an accumulator spring and in addition each containing an anti-gravity spring between the transverse beam and structure of the pivot bearing, said anti-gravity springs being arranged to absorb the mass weight of said supports and screening elements. l a

2. The vibratory screening apparatus of the counter oscillating type as set forth in claim 1, wherein the pivot bearings are provided with spacer guides and the adjustable anti-gravity springs are arranged between these spacer guides and the transverse beam.

7 References Cited in thefile of this patent UNITED STATES PATENTS 1,997,499 Schieferstein et al. Apr. 9, 1935 12 ,285,348 Morgan June 2, 1942 FOREIGN PATENTS 945,548 Germany July 12, 1956 

